I improved the regex given here, to take into account your comments :
pregreplace('@((https?://)?(\w+.[-\w.]+)+\w(:\d+)?(/([-\w/.](\?\S+)?)?))@', '$1', $text);

Now with this regex, the links can be without any http:// or https:// block (like www.exemple.com) and can have multiple /folder/subfolder/file.htm after the domain, and finally "-" are considered as part as a standard URL.

Thanks for the first regex that helped me a lot find this one ! I hope mine will help the others.